In known forms of aerosol valves and associated product containers, liquified propellants are filled into the can with the product to be dispensed. Such propellants provide relatively constant pressure and product flow rates as the product is dispensed through the aerosol valve. Liquified propellants have certain disadvantages, however, relating to cost, volatility, etc. It has long been proposed to use non-liquified, compressed gases such as nitrogen, carbon dioxide, etc. for the propellant in the aerosol container. Compressed gases of course are relatively inexpensive, but suffer from the disadvantage that as the product is dispensed from the can, the pressure within the can decreases substantially with the result that there is a substantially decreasing discharge rate for the product.
Numerous attempts have been made to overcome the above-noted disadvantage of using compressed gases, including providing flow regulators of one design or another in the flow path of the product and compressed gas as they are dispensed. In one known construction, the subject of Japanese Patent No. 2,512,368 for "Flow Regulating Valve" granted Apr. 16, 1996, a flow regulator is placed upstream of an aerosol valve within the valve housing. A conical valve seat is disclosed which has a single groove therein which interacts with an elastic regulating member having a portion of a spherical surface, the regulating member pressing against the conical valve seat and into the single groove under the influence of higher pressures of compressed gas used as a propellant. A further version is also disclosed wherein a conical valve seat with a large number of grooves is placed within an actuator downstream of the aerosol valve, and likewise interacts with the regulating member pressing into the grooves under the influence of the higher pressures of compressed gas. In each instance, the regulator throttles the flow discharge according to the changes in pressure as the compressed gas and product are discharged, in an attempt to obtain a relatively uniform product discharge rate. Higher gas pressures cause the regulating member to extend further into the grooves than is the case with lower gas pressures, thus varying the cross-sectional flow areas of the grooves. The grooves of the system according to the above patent are rectangular, the above-noted patent does not disclose the material of the regulating material and its relative hardness or softness, and no dimensions of the grooves are disclosed. A system according to the above-noted patent does not obtain highly uniform product discharge rates. Further, the system according to the above noted patent is more complicated in its molding and assembly due to a plurality of inwardly extending bevelled projections to secure the regulating member and which the regulating member must be pressed beyond, during assembly.